Can't chase that store credit? These apps do it for you

It’s among the most frustrating aspects of Christmas shopping: Knowing that many of the gifts purchased in the days leading up to the holiday will be deeply discounted on Dec. 26.

Though many stores have policies that will credit the difference between the new and old price if shoppers produce receipts within a certain time, only the most organized and thrifty are likely to make the effort to claim their money.

Rejoice, lazy shoppers: Earny.co, Paribus.co and Slice.com will either secure the refund or help you obtain it.

There are some caveats, however. These services only work on items purchased online. Still, the savings can be significant. The National Retail Federation predicts that online holiday shopping this year will increase between 7% and 10%, to as much as $117 billion. Also, these services need access to your email to search for correspondence from retailers that include the purchase receipts.

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Not to worry, said Eric Glyman, a co-founder of Brooklyn-based Paribus, which runs both a website and an app, and was purchased by Capital One for an undisclosed sum earlier this year. He said Paribus doesn’t require your email password and that its computers only look for messages from the 25 retailers it works with, including Macy’s, Target, Old Navy and Best Buy.

If Paribus’ computer finds a price drop, it will automatically contact the retailer and secure the discount. Shoppers must pay Paribus 25% of their savings as a finder’s fee through a credit card left on file with the company. Paribus also searches for coupons and other promotions shoppers may have missed when making their purchases.

“If you are busy person, you don’t have time to watch prices or read all these store policies,” said Mr. Glyman. “It is a job well-suited to a computer that can read a lot of information.”

Like Paribus, Earny.co takes a 25% fee. However, Earny.co asks users to submit their email passwords.

Slice, which is both a website and an app, is free but doesn’t automatically secure the discount. Instead, it informs shoppers that they are entitled to a refund and helps them secure it. The company estimates it has saved customers an average of $30 per price drop.

Earlier this month, Slice introduced an app-only product called Slice Drop which is even more focused on helping shoppers save money. Unlike Slice, it doesn’t track customers’ packages or spending. However, it streamlines the process to getting a refund to just one click on a link. It also alerts shoppers to price drops on different merchandise by retailer.

Slice Drop will also guarantee refunds of up to $20 a month for purchases from Amazon.com even though the online retailer doesn’t offer such a policy. A company spokeswoman said she didn’t know how long that promotion would continue, although if and when it is stopped, Slice Drop will still offer a $10 a month guarantee.